System and method for determining position and velocity of an intruder from an array of sensors

Abstract

This invention relates to a system and method for determining velocity, direction, position, profile and confidence information of a target such as an intruder from alarms generated by the intruder passing by an array of spaced sensors. The system comprises a processor, the primary element of which is a velocity-position matrix comprising a plurality of information storage cells in the form of counters. The cells are arranged in a plurality of adjacent rows and adjacent columns corresponding to target velocity and position, respectively. Each sensor alarm is entered as a count into cells in those columns which correspond to sensor deployment and the count in each cell is shifted to the adjacent cell in the same row by auxiliary equipment at different rates for the different rows to provide a velocity determination capability. Counts are subtracted from the cells in the columns corresponding to sensor locations when no alarm is given by the particular sensor. Apparatus is provided to scan the matrix for determination of maximum counts in the cells to indicate the position and velocity of the intruder or target. Direction, profile or target length, and confidence information are derived by logic circuits through interpretation of the position and velocity information.

What is claimed is: 
     
       1. A method of automatically determining velocity and direction of movement of target passing an array of sensors, comprising the steps of spacing said sensors at predetermined distances along an area under surveillance,   operatively connecting said sensors to correspondingly spaced columns of a plurality of data storage cells arranged in a matrix comprising said columns and transverse rows of said cells,   increasing the counts in the cells of each column associated with a sensor that detects a target within a predetermined interval,   decreasing the counts in cells of each column associated with a sensor that does not detect a target within said interval,   periodically shifting the counts in one direction from each cell to the cell in the adjacent column at different shift rates for different rows corresponding to different target velocities and repeating the count increasing and decreasing steps after each shifting step,   periodically determining the row having the maximum sum of counts and identifying the shift rate of that row with the target velocity,   scanning in one direction the cells in the target velocity row and determining the cell having a count not less than a predetermined number whereby to establish the location of the target relative to the sensor array.   
     
     
       2. A system for automatically determining velocity and direction of a target comprising a plurality of spaced sensors capable of sequentially detecting the target, each of said sensors producing an output when a target is within range thereof, a matrix having a plurality of data storage cells arranged in a plurality of columns and in a plurality of transverse rows, each of said cells comprising a counter capable of having counts automatically added thereto and automatically subtracted therefrom and automatically shifted to adjacent cells in adjacent columns,     means for connecting the outputs of said sensors to certain sensor columns, respectively, in said matrix whereby each periodically produced output from each sensor causes the count in the cells in the associated sensor column to increase, said sensor columns being spaced in the matrix in correspondence with the physical spacing of the sensors, respectively,   means for automatically subtracting a count from each of the cells in each sensor column when the associated sensor does not periodically detect a target,   means for automatically shifting in one direction the count in each cell of certain of said rows to the adjacent cell in the adjacent column at different shift rates for each of said certain rows and for automatically shifting in the opposite direction the count in each cell in others of said rows to the adjacent cell in the adjacent column at different shift rates for each of said others of said rows, said different shift rates corresponding to different velocities of movement of the target relative to said sensors,     means for automatically determining the one row having the greatest sum of cell counts whereby to indicate the velocity and direction of movement of said target, and   utilization means responsive to the output of said determining means.   
     
     
       3. The system according to claim 2 including means for automatically scanning said one row in a direction opposite the corresponding target movement direction and identifying the first cell having a count not less than a predetermined value whereby the location of the column containing said first cell relative to other columns in the matrix provides an indication of the position of the target relative to said plurality of sensors. 
     
     
       4. The system according to claim 3 in which said last named means includes means for identifying additional cells having counts not less than said predetermined number whereby the number of such additional cells indicates the profile of said target. 
     
     
       5. Apparatus for determining the velocity, direction of movement and position of a moving object, comprising an array of spaced sensors adapted to periodically generate output signals in response to relative movement of said object within detection range of the sensors,   a memory matrix comprising a plurality of cells arranged in a plurality of adjacent columns and in a plurality of stacked rows extending generally transversely of said columns, the width of said columns corresponding to a portion of the length of said array, each of said cells comprising a counter having a predetermined count storage capacity,     means for operatively connecting the outputs of said sensors to the cells in an equal number of certain columns, respectively, in said matrix, the inter-columnar spacing of adjacent ones of said certain columns corresponding to intersensor spacing of adjacent sensors in said array,   means for adding one count to all cells in each of said certain columns having an associated sensor and producing an output during each reporting period of the sensor in response to a detected object,   means for subtracting one count from all cells in each of said certain columns having an associated sensor not producing an output during each reporting period of the sensor,   timing means having output signals with different repetition rates connected to the cells in different rows, respectively, of a first set of rows, the cells in said first set of rows being responsive to said output signals to shift in a first direction the count in each cell in said first set of rows to the adjacent cell in the adjacent column whereby the receiving cell cumulates said counts,   timing means having output signals with different repetition rates connected to the cells in different rows, respectively, of a second set of rows, the cells in said second set of cells being responsive to said output signals to shift in a second direction opposite said first direction the count in each cell in said second set of rows to the adjacent cell in the adjacent column whereby the receiving cell cumulates said counts,   first circuit means connected to said rows of cells and automatically adding the counts in the cells in said rows and identifying the one row having the maximum count whereby the shift rate and row set associated with said one row indicate the velocity and direction of movement of the object,   means for determining the count in the cell in said one row having the maximum value (max count) relative to other cells in said one row,   means for dividing said max count by 2 to determine the half-max number,   second circuit means for automatically examining the cells in said one row in a direction opposite from the direction of shift of counts in said one row and identifying the first cell having a count not less than said half-max number whereby the relative position in the matrix of the column containing said first cell identifies the relative position of the object in the array of sensors, and   display apparatus connected to said first and second circuit means to indicate the velocity and direction of movement and position of said object.   
     
     
       6. Apparatus according to claim 5 in which said second circuit means is responsive to the counts in each of other cells in said one row following said first cell having a count not less than said half-max number for relating the number and location of said other cells relative to said first cell to indicate the profile of said object. 
     
     
       7. A method for determining the position and velocity of an intruder from an array of sensors consisting of the steps of spacing said sensors at predetermined distances along an area under surveillance,   arranging a plurality of data storage cells into a plurality of adjacent columns and transversely stacked rows, each of said cells being characterized by a count accumulating capacity and being capable of permitting the total count thereof to be shifted to the adjacent cell in the adjacent column,   inputting the outputs of said sensors to certain of said columns of cells, respectively, having spaced positions corresponding to the spaced positions of said sensors, said certain of said columns defining sensor columns,   periodically adding one count to each of the cells in said sensor columns associated with sensors that are generating alarm signals,   periodically subtracting one count from each of the cells in said sensor columns associated with sensors that are not generating alarm signals,   automatically shifting counts in one direction from the cells in each column to adjacent cells in adjacent columns at different rates for the cells in certain of the plurality of rows corresponding to predetermined different velocities at which objects move by the array of sensors,   automatically shifting counts in a direction opposite said one direction from the cells in each column to adjacent cells in adjacent columns at different rates for the cells in others of the plurality of rows corresponding to said predetermined different velocities,   automatically scanning said rows of cells and determining the row having the maximum sum of counts whereby to identify the velocity row and to relate the direction and velocity associated with that row to the direction and velocity of the object,   automatically searching said velocity row in the direction opposite from the object movement direction and identifying the first column containing a cell having a count not less than a predetermined number whereby to relate the position of the object with the position associated with said first column of cells,   continuing said searching of said velocity row and identifying each column after said first column having cells in said velocity row with counts greater than said predetermined number whereby to establish that the object comprises a group and to determine the length of the object group, and   utilizing data representing said object velocity direction, position and length.   
     
     
       8. The method according to claim 7 in which said predetermined number is a half-max number calculated by determining the maximum single cell count (max count) in said velocity row and dividing said max count by 2 whereby the resultant is the half-max number, the value of said half-max number being indicative of the degree of reliability of the derived object information. 
     
     
       9. A method for determining the position and velocity of an intruder from an array of sensors consisting of the steps of spacing said sensors at predetermined distances along an areea under surveillance,   arranging a plurality of data storage cells into a plurality of adjacent columns and transversely stacked rows, each of said cells being characterized by a count accumulating capacity and being capable of permitting the total count thereof to be shifted to the adjacent cell in the adjacent column,   inputting the outputs of said sensors to certain of said columns of cells, respectively, having spaced positions corresponding to the spaced positions of said sensors, said certain of said columns defining sensor columns,   periodically adding one count to each of the cells in said sensor columns associated with sensors that are generating alarm signals,   periodically subtracting one count from each of the cells in said sensor columns associated with sensors that are not generating alarm signals,   automatically shifting counts in one direction from the cells in each column to adjacent cells in adjacent columns at different rates for the cells in certain of the plurality of rows corresponding to predetermined different velocities at which objects move by the array of sensors,   automatically shifting counts in a direction opposite said one direction from the cells in each column to adjacent cells in adjacent columns at different rates for the cells in others of the plurality of rows corresponding to said predetermined different velocities,   automatically scanning said rows of cells and determining the row having the maximum sum of counts whereby to identify the velocity row and to relate the direction and velocity associated with that row to the direction and velocity of the object, and   utilizing data representing said object velocity and direction.   
     
     
       10. A method for determining the position and velocity of an intruder from an array of sensors consisting of the steps of spacing said sensors at predetermined distances along an area under surveillance,   arranging a plurality of data storage cells into a plurality of adjacent columns and transversely stacked rows, each of said cells being characterized by a count accumulating capacity and being capable of permitting the total count thereof to be shifted to the adjacent cell in the adjacent column,   inputting the outputs of said sensors to certain of said columns of cells, respectively, having spaced positions corresponding to the spaced positions of said sensors, said certain of said columns defining sensor columns,   periodically adding one count to each of the cells in said sensor columns associated with sensors that are generating alarm signals,   periodically subtracting one count from each of the cells in said sensor columns associated with sensors that are not generating alarm signals,   automatically shifting counts in one direction from the cells in each column to adjacent cells in adjacent columns at different rates for the cells in certain of the plurality of rows corresponding to predetermined different velocities at which objects move by the array of sensors,   automatically shifting counts in a direction opposite said one direction from the cells in each column to adjacent cells in adjacent columns at different rates for the cells in others of the plurality of rows corresponding to said predetermined different velocities,   automatically scanning said rows of cells and determining the rows having the maximum sum of counts whereby to identify the velocity row and to relate the direction and velocity associated with that row to the direction and velocity of the object,   automatically searching said velocity row in the direction opposite from the object movement direction and identifying the first column containing a cell having a count not less than a predetermined number whereby to relate the position of the object with the position associated with said first column of cells, and   utilizing data representing said object velocity, direction and position.   
     
     
       11. A method for determining the position and velocity of an intruder from an array of sensors consisting of the steps of spacing said sensors at predetermined distances along an area under surveillance,   arranging a plurality of data storage cells into a plurality of adjacent columns and transversely stacked rows, each of said cells being characterized by a count accumulating capacity and being capable of permitting the total count thereof to be shifted to the adjacent cell in the adjacent column,   inputting the outputs of said sensors to certain of said columns of cells, respectively, having spaced positions corresponding to the spaced positions of said sensors, said certain of said columns defining sensor columns,   periodically adding one count to each of the cells in said sensor columns associated with sensors that are generating alarm signals,   periodically subtracting one count from each of the cells in said sensor columns associated with sensors that are not generating alarm signals,   automatically shifting counts in one direction from the cells in each column to adjacent cells in adjacent columns at different rates for the cells in certain of the plurality of rows corresponding to predetermined different velocities at which objects move by the array of sensors,   automatically shifting counts in a direction opposite said one direction from the cells in each column to adjacent cells in adjacent columns at different rates for the cells in others of the plurality of rows corresponding to said predetermined different velocities,   automatically scanning said rows of cells and determining the row having the maximum sum of counts whereby to identify the velocity row and to relate the direction and velocity associated with that row to the direction and velocity of the object,   automatically determining the maximum single cell count (max count) in said velocity row,   automatically dividing said max count by 2 whereby the resultant is the half-max number,   automatically searching said velocity row in the direction opposite from the object movement direction and identifying the first column containing a cell having a count not less than the half-max number whereby to relate the position of the object with the position associated with said first column of cells, and   utilizing data representing said object velocity, direction and position.   
     
     
       12. The method according to claim 11 including the steps of further searching said velocity row and identifying each column after said first column having cells in said velocity row with counts not less than said half-max number whereby to establish that the object comprises a group and to determine the length of the object group, and   utilizing data representing the length of said object group.